Best Bullet

Recently purchased a Remington 700 SPS Stainless .300 RUM with 26" barrel. I have never tried to shoot more then 200 yards so I am very new to long range shooting. I shoot a really good group at 100-200 and really would like to learn to shoot to about 500-600 and maybe even further if possible. I will be hunting mainly deer with this gun with the yearly elk trip. What would be the best bullet for this gun?

Well with very general questions like you have it would be best to use the search function here and do some research. Then after you have learned a little bit you can ask more specific questions AND get more specific, helpful answers.

That's if you're handloading your own ammunition. If you're looking for a really good factory load, you should check out the Remington Power Level line loaded with 180g Scirocco bullets. For factory ammo, they were extremely accurate in my rifle (a Remington Sendero SF2).

I would really like to start loading my own. Only problem is that I don't have any experience doing it nor the equipment. I am looking into getting a press and I have a buddy at the local shooting range that said he will teach me.